Contour guide

Contour is an EQ manager for the CrinEar Protocol Micro, Protocol Max and FiiO KA15. The dongle keeps its EQ inside, so the EQ works with every app and every device you plug it into.

The film was shot with the Protocol Micro, which has 8 bands. The Protocol Max and the FiiO KA15 have 10 bands instead of 8.

Contour changes that EQ from an Android phone, with no account and no internet. A fresh install comes with three profiles to start from: PROFILE 1 (flat), NIGHTFALL and DUSK.

Plug in your Protocol Micro, Max or KA15. The pill in the top right corner of the Library shows its status:

• NO DAC - nothing is plugged in. Tap it to check again.
• TAP TO CONNECT - the dongle is there, but Android hasn't allowed access yet. Tap it, and allow.
• CONNECTED, with a green dot - you're ready.

Tip: when Android offers to open Contour, tick "always", and next time it connects by itself.

Tap a profile to open it on the EQ page. HOLD TO SEND is the only button that writes to the dongle. Hold it until it fills; a tap does nothing. Contour writes every band and the preamp, reads them back, and stores them only if everything matches.

ON DAC means this profile is now in the dongle's memory. Unplug it and use it anywhere. The Library marks it ON DAC too, so you always know what the dongle holds.

FiiO KA15. The KA15 has three user slots. Pick USER1, USER2 or USER3 in the row above HOLD TO SEND; the row shows the name each slot holds. Contour writes the profile to that slot and names the slot after the profile (up to 7 letters and digits). Long-press a slot to rename it without changing its EQ. While it reads or writes, Contour plays a silent stream to the KA15, because the KA15 answers only while audio is streaming to it; your music keeps playing.

To make a new profile, tap the empty card with the plus. FLAT gives you one flat band at 1 kHz.

The white line is what your EQ does to the sound. Each numbered dot is a band: drag it sideways for frequency, up and down for gain. Long-press an empty spot to add a band right there.

Under the graph, pick the filter type: PEAK works around the frequency, LOW SHELF below it, HIGH SHELF above it.

The FREQ, GAIN and Q sliders move from where they are, so a touch never makes the value jump. Slow drags give fine steps, and when you lift your finger, the value stays.

With PREAMP on AUTO, Contour lowers it just enough to stop your boosts from clipping. Everything saves as you go.

Long-press a card to edit its name and description, and to pick an icon. A good habit: one profile per pair of headphones, named after them. Then open it and send it with HOLD TO SEND.

EQ and LIBRARY are also a swipe apart.

Tap a dot or a chip to select its band. Double-tap a dot to reset its gain to 0 dB. Pinch to make the selected band narrower or wider: that's its Q.

The + chip adds a band, up to eight. Long-press a chip to bypass a band, enable it again, or delete it.

One fast swipe on FREQ covers the whole range. For an exact value, tap the number and type it.

PREAMP switches between AUTO and MANUAL. In MANUAL, drag it or type a value, in whole dB from -30 to 0. A quieter sound after sending is the preamp making room for your boosts.

Compare. A/B works while the profile is ON DAC. Tap it, and the curve switches off but the preamp stays, so you hear the difference at the same volume. Tap A/B again, and your EQ is back. A/B never saves anything to the dongle. A/B is for the Protocol Micro only for now; it is not available on the Protocol Max or KA15 yet.

Undo. The two arrows by the profile name work like Ctrl+Z on a computer: undo takes back your last change, whatever it was, and redo steps forward again. One touch is one step, however far you drag. Each profile keeps up to 100 steps, even after you close the app.

Clear. CLEAR EQ leaves one flat band. That's a change like any other, so undo brings it straight back.

Last sent. LAST SENT appears whenever the profile differs from what's on the dongle. Tap it, and you're back to the version the dongle holds. Or send the new version instead.

Duplicate is handy before you experiment: long-press a card and tap DUPLICATE.

Swipe a card left to ARCHIVE or DELETE it. Both offer UNDO for five seconds.

Archived profiles wait in a folded section at the bottom of the Library. Open it, and swipe a card to RESTORE it.

SHARE (long-press a card) sends a profile as plain text, in the Equalizer APO format. Keep a copy somewhere: profiles live only on your phone.

PASTE (tap the + card) reads the same format, from AutoEQ, Squiglink or an EQ by Ear export. Check the curve before sending.

FROM DAC (tap the + card) saves what the dongle holds right now as a new profile.

Swiping the + card left saves every profile as its LAST SENT version, without sending anything. It asks first, and it can't be undone.

Long-press the status pill for the service screen. It shows the raw state of the dongle, and a USB log for bug reports. Read from DAC reads it again. Restore flat writes a flat EQ to the dongle, after asking first.

ABOUT & LICENCES, at the bottom of the Library, shows the version and the open-source licences.

Contour never lets you go past the dongle's limits, so what you see is what it plays: 8 bands on the Protocol Micro, 10 on the Protocol Max, gain -10 to +10 dB, Q 0.1 to 10, 20 Hz to 20 kHz, preamp -30 to 0 dB. The FiiO KA15 has 10 bands, gain -12 to +12 dB, shelf Q up to 7.07 and preamp -24 to 0 dB. The Micro has no real high shelf, so Contour sends a mirrored low shelf plus preamp: the same curve. The Max and KA15 have native shelf filters and need no mirroring. If the KA15 stops answering after a save, unplug it and plug it back in.

• Stuck on NO DAC? Plug the dongle in again, without adapters or hubs.
• Sending failed? Hold the button again. Usually the dongle moved.
• PASTE greyed out? The clipboard holds no EQ that Contour understands. Copy the text again.

Installing, updating and checking the APK are on the install page.

Other dongles may follow, once someone confirms them on real hardware. Contour is open source: the code and the releases are on GitHub, and questions and bug reports go to GitHub Issues.